def test_initial_state_vector():
qubits = cirq.LineQubit.range(3)
args = cirq.DensityMatrixSimulationState(qubits=qubits,
initial_state=np.full(
(8, ), 1 / np.sqrt(8)),
dtype=np.complex64)
assert args.target_tensor.shape == (2, 2, 2, 2, 2, 2)
args2 = cirq.DensityMatrixSimulationState(qubits=qubits,
initial_state=np.full(
(2, 2, 2), 1 / np.sqrt(8)),
dtype=np.complex64)
assert args2.target_tensor.shape == (2, 2, 2, 2, 2, 2)
def test_with_qubits():
original = cirq.DensityMatrixSimulationState(
qubits=cirq.LineQubit.range(1), initial_state=1, dtype=np.complex64)
extened = original.with_qubits(cirq.LineQubit.range(1, 2))
np.testing.assert_almost_equal(
extened.target_tensor,
cirq.density_matrix_kronecker_product(
np.array([[0, 0], [0, 1]], dtype=np.complex64),
np.array([[1, 0], [0, 0]], dtype=np.complex64),
),
)
def test_initial_state_bad_shape():
qubits = cirq.LineQubit.range(3)
with pytest.raises(ValueError, match="Invalid quantum state"):
cirq.DensityMatrixSimulationState(qubits=qubits,
initial_state=np.full((4, ), 1 / 2),
dtype=np.complex64)
with pytest.raises(ValueError, match="Invalid quantum state"):
cirq.DensityMatrixSimulationState(qubits=qubits,
initial_state=np.full((2, 2), 1 / 2),
dtype=np.complex64)
with pytest.raises(ValueError, match="Invalid quantum state"):
cirq.DensityMatrixSimulationState(qubits=qubits,
initial_state=np.full((4, 4), 1 / 4),
dtype=np.complex64)
with pytest.raises(ValueError, match="Invalid quantum state"):
cirq.DensityMatrixSimulationState(qubits=qubits,
initial_state=np.full((2, 2, 2, 2),
1 / 4),
dtype=np.complex64)
def test_cannot_act():
class NoDetails:
pass
args = cirq.DensityMatrixSimulationState(
qubits=cirq.LineQubit.range(1),
prng=np.random.RandomState(),
initial_state=0,
dtype=np.complex64,
)
with pytest.raises(TypeError, match="Can't simulate operations"):
cirq.act_on(NoDetails(), args, qubits=())
def test_default_parameter():
qid_shape = (2, )
tensor = cirq.to_valid_density_matrix(0,
len(qid_shape),
qid_shape=qid_shape,
dtype=np.complex64)
args = cirq.DensityMatrixSimulationState(qubits=cirq.LineQubit.range(1),
initial_state=0)
np.testing.assert_almost_equal(args.target_tensor, tensor)
assert len(args.available_buffer) == 3
for buffer in args.available_buffer:
assert buffer.shape == tensor.shape
assert buffer.dtype == tensor.dtype
assert args.qid_shape == qid_shape
def test_decomposed_fallback():
class Composite(cirq.Gate):
def num_qubits(self) -> int:
return 1
def _decompose_(self, qubits):
yield cirq.X(*qubits)
args = cirq.DensityMatrixSimulationState(
qubits=cirq.LineQubit.range(1),
prng=np.random.RandomState(),
initial_state=0,
dtype=np.complex64,
)
cirq.act_on(Composite(), args, cirq.LineQubit.range(1))
np.testing.assert_allclose(
args.target_tensor,
cirq.one_hot(index=(1, 1), shape=(2, 2), dtype=np.complex64))
def test_shallow_copy_buffers():
args = cirq.DensityMatrixSimulationState(qubits=cirq.LineQubit.range(1),
initial_state=0)
copy = args.copy(deep_copy_buffers=False)
assert copy.available_buffer is args.available_buffer